So, I took the truck in to the dealer and they said it was the exhaust making the ratel/squealing sound. they put a old exhaust on it that they had in there shop that had 130k on it and it still made the same sounds and GM will not replace it, so that tells me its not the exhaust. any way they had GM look into the problem and they came back and said, this is a normal noise and there is nothing they can do to fix the problem..... NOT HAPPY!! the service guy told my wife to put in a claim to GM and and ask for my money back and give back the truck... WOW!! GM also said that the noise is to make the truck sound like a V8, HAHAHAHA, Bull SH*T!! they also started 2 brand new high country V8 6.2L they had on the lot and they also made the same noise. to bad they didn't have a Chevy trail boss to show me . So now I'm stuck with this and no fix to the problem. this was the first time I ever bought a Chevy and will be the Last!! GM should be ashamed of them self's... I could go on and on.....